Various types of quick disconnect couplings have been produced to facilitate connecting and disconnecting components of a fluid conduit, such as a hydraulic line. Examples of quick disconnect couplings of this type are illustrated and described in U.S. Pat. Nos. 2,333,423; 3,897,091; 4,392,513; and 5,129,621. In each of these coupling designs, a valve element is located in each coupling member for quickly closing the flow passageway when the coupling members are disconnected. However, a significant limitation of these valve designs is that the valve element remains in the flow passageway when the coupling members are coupled, thus partially obstructing the flow. This can result in an undesirable increase in pressure drop at the coupling. Also, these designs are not well-suited for systems which convey solids, such as slurries or pneumatically conveyed solids, since the solids can become lodged in the flow restrictions caused by the valve elements.